The present invention generally relates to a fuel pump for an internal combustion engine. More specifically, the present invention relates to a fuel pump that provides dual chamber pumping action with a single reciprocating plunger.
In low pressure applications, on the order of 40-60 psi, turbine impeller fuel pumps can be used to deliver fuel from the fuel tank in an automobile to the fuel rail and cylinders of the engine. However, conventional turbine impeller fuel pumps cannot deliver fuel at the pressures required in high pressure fuel systems, which are on the order of 300 psi. Piston type fuel pumps are more capable of delivering the fuel at these higher fuel pressures, however, the piston pumps have some significant drawbacks. A single piston pump delivers fuel at fluctuating pressures due to the pressure drops during the intake stroke of the piston. To alleviate the pressure fluctuations, multiple piston pumps have been developed, wherein the timing of the strokes of the pistons is staggered to reduce the pressure fluctuations in the fuel flow. However, conventional multiple piston pumps are large, and have many parts, thereby making them heavy and expensive. Therefore, there is a need for a piston fuel pump that provides a relatively stable fuel pressure with a single piston.